Vacuum cleaners have been known for some time, both for domestic and industrial use, which include systems for scrubbing sucked air that cause the air to be purified from dirt particles to bubble into a liquid.
In order to improve scrubbing efficiency, it is also known to provide a dynamic separation system in the upper portion of the housing where the scrubbing liquid is collected, which consists of a rotating element having radial blades with passage spaces therebetween.
This type of separation system is actuated by a motor or by the sucking system itself, and rotates to smash dirt particles down that may be suspended in the air streams that have entered into the housing through an inflow opening.
The housing is also provided with an outflow opening for the scrubbed air, and the separation system is typically placed at the entry to such outflow opening, such that only air streams that have been completely purified can exit through the outflow opening and be later directed toward the motor system for cooling and be finally delivered into the surrounding environment again.
In other words, particulate matter that is still suspended within the housing is sucked toward the outflow opening, but collides against the radial blades of the moving rotor and falls into the pool of scrubbing liquid placed underneath.
The prior art has a number of drawbacks.
A first drawback is that the rotor blades are always substantially damp due to moisture in the housing where the rotor is turning and that the particles hitting the blades are prone to sticking to the surfaces of the blades, progressively forming a dirt layer, which may increase over time and plug passage spaces, blocking the operation of the vacuum cleaner.
Such plugging requires that the vacuum cleaner be stopped and disassembled, in order to clean the blades of the rotor and restore the passages among the blades, and later be re-assembled to continue use.
Another drawback is that the inflow opening for the air streams is provided on a side of the housing, that is, crosses through a lateral wall of the housing, and is coupled to a tube segment that extends inside the housing and ends under the free surface of the scrubbing liquid.
Therefore, the bubbling of the air streams to be scrubbed occurs mainly at the outlet of the tube that extends into the scrubbing liquid, while in other areas of the housing the bubbling and, accordingly, the efficiency of filtration is reduced because the liquid has a natural tendency to attenuate turbulent flow.
Still another drawback is that typically the housing that contains the scrubbing liquid (normally water) is constructed with transparent walls, which enable a continuous view from the outside into the housing and a continuous view of the volume of dirt gathered in the liquid.
When the liquid becomes very dirty, it may assume a dark and opaque appearance that causes a feeling of repulsion and an impression of low hygiene in the users.